In automotive suspension systems it is customary to use elastic joints each comprising a pair of members rigid with their associated bodies, i.e. the wheelbase and the chassis, which are resiliently interconnected so as to provide a universal elastic restoring force uniformly resisting a relative displacement of the two bodies in any direction.
Such joints with uniform modulus of elasticity, however, do not respond optimally to actual driving conditions requiring different degrees of relative mobility in mutually orthogonal directions. Thus, a tall vehicle such as a truck should have a suspension have a suspension capable of absorbing road shocks as well as accelerations in the direction of travel but should not sway excessively in a direction transverse thereto.